Mutations affecting the operator of recA will be characterized by nucleotide sequencing techniques. Mutations affecting the activity of RecAp will be mapped relative to each other by amino acid sequencing techniques. The recF product will be identified and its in vivo functional relationship with recA further investigated. Mutations affecting recombination by the RecE and RecF pathways will be further characterized and if possible the gene products affected will be identified. Additional mutants blocked in steps in recombination not heretofore affected will be sought. recA independent recombination accomplished by transposable elements and by conjugationally transmissible plasmids will be further studied to characterize the sequences and enzymatic mechanisms involved. Suitable systems to detect intermediates and end products in recombination will be sought.